PDC2015: Impact scenario

Note: This article concerns a hypothetical asteroid scenario. The information described in this article does not concern a real world event but is based on the practise scenario used at the PDC2015.


 

The planetary defense conference 2015 has gone through its last day this Friday, and this day was fully dedicated to the conclusion of the PDC2015 impact scenario. During the conference all the experts on planetary defence enacted a scenario in which an asteroid is on collision course with Earth. Using such a scenario the people can learn how political leaders, citizens, and the media would respond in the case of such a threat. 

 

Day 1: An asteroid threat detected

An map of day 1 of the PDC2015 impact scenario with the impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

A map of day 1 of the PDC2015 impact scenario with the impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

On the first day of the conference the organizing committee presented the following scenario: A Near-Earth Asteroid is predicted to pass very close to the Earth on the 3rd of September 2022. The asteroid (designated 2015 PDC) has a chance of 1 in 110 of hitting the Earth. If the Earth would be hit by the asteroid it would strike somewhere on the corridor shown in the picture: The Middle-East, across South-Asia and the Pacific would all be of risk for the impact.

To discuss this scenario the experts were split in four groups. The first group represents the world leaders of countries that are in the path of the asteroid and are thus directly under risk of an impact. The second group represents all other leaders whose countries are not under direct threat from an impact. The third group are people who are living in the countries at risks and whose homes are under risk of being hit. Finally, the fourth group represents the media and needs to estimate how the media would react on this scenario.

See the day 1 scenario information here: http://neo.jpl.nasa.gov/pdc15/day1.html

 

Day 2: April 2016, 43% chance of impact

An image of day 2 of the PDC2015 impact scenario with the asteroid possible tracjectories. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

An image of day 2 of the PDC2015 impact scenario with the asteroid possible tracjectories. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

On the second day of the conference the organisation committee presented the participants with an updated scenario. The first day the scenario took place in June 2015, and the impact chance was smaller than a per cent. Now on day 2 the scenario made a jump in time to April 2016. The asteroid had passed through one orbit around the sun and now it could again be observed more closely again, allowing its orbit to be determined better. It however did not bring good news: The new orbit showed that the asteroid now has a 43% chance of hitting Earth! The image given shows the possible location of the asteroid (the red dots) at the possible time of impact.

The reaction of the experts was still one of doubt. As there was still a larger chance that the asteroid would miss the Earth compared to it actually hitting, all parties did not decide to start a deflection mission yet, but all parties did ask for extra information. Everyone wanted to know more about the asteroid and its orbit. More information was however not available as there were no telescopes or spacecraft available to observe the asteroid more closely.

For all the details of day 2, take a look at this site: http://neo.jpl.nasa.gov/pdc15/day2.html

 

Days 3 and 4: Certain impact, and kinetic impactors on their way

A map of day 4 of the PDC2015 impact scenario with the reduced impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

A map of day 4 of the PDC2015 impact scenario with the reduced impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

On day 3 and 4 the impact scenario became more definitive when the scenario jumped from December 2016 (day 3) to August 2019 (day 4). The reason for these large time-steps between the subsequent days is that due to the orbit of the asteroid around the Sun, it is not visible all the time. It is often hidden behind the sun from the point of view of the Earth, making it difficult to observe its size and orbit.

On day 3 it was announced that the impact of the asteroid was now a 100% certain. On day 4 the exact impact zone was then released: An impact was expected within the South-China sea. The impact of an asteroid between 150 and 250 meters (as expected in the scenario) would trigger a large tsunami that would impact all the coasts along this sea, hitting China, Vietnam, the Philippines, Malaysia, Brunei, Taiwan, and Indonesia. In total it would put more than 80 million people at risk. To mitigate the threat there are in total six kinetic impactors underway to push the asteroid out of its course so that it will miss Earth.

A orbit diagram for the PDC2015 impact scenario. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

A orbit diagram for the PDC2015 impact scenario. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

Within the discussion among the experts it quickly became clear that there was quite a bit of mistrust among the different country leaders concerning the kinetic impactor missions, and also specifically concerning a possible nuclear blast deflection option! The country leaders and the inhabitants of the countries around the South-China-Sea were worried if the kinetic impactors would actually be effective, and if it would be enough to deflect the asteroid. Also countries were suspicious of each other if any of them were developing nuclear deflection options, as they argued that although such a method could be effective against asteroids, it could also be used as a weapon.

For the detailed information provided on day 3, see here: http://neo.jpl.nasa.gov/pdc15/day3.html

And for the details of day 4, take a look at http://neo.jpl.nasa.gov/pdc15/day4.html 

 

Day 5: Kinetic impactors not fully effective!

On day 5, the last day of the conference, the speed of the scenario was ramped up, and a total of three “press-releases” were presented to the participants during the day. The first one was already ominous enough: The date is January the 18th, 2021 (1.5 years before impact) and the kinetic impactors only have had partially effect. The asteroid turned out to be a lose rubble pile, and after the second kinetic impactor hit, the object was broken in two big pieces!

A map of day 5 of the PDC2015 impact scenario with a renewed, widened impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

A map of day 5 of the PDC2015 impact scenario with a renewed, widened impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

The bigger piece was fortunately pushed away by the impactors and no longer poses a threat to the Earth. The smaller piece however, which is still 60 to 100 metres large, is still on impact course with the Earth. Because of the impactors the orbit of the object is again uncertain, and therefore the impact corridor has widened again (see image above).

The last map of day 5 of the PDC2015 impact scenario with the final impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

The last map of day 5 of the PDC2015 impact scenario with the final impact risk corridor. (Image credit: IAA; JPL. Note: Hypothetical impact scenario, no real world event.)

Later in the day the scenario progressed further and it ended on August the 27th, 2022, about a month before impact. The impact location had by now been determined to be at one of the worst possible locations: in the middle of Dhaka, the capital city of Bangladesh. Dhaka is the tenth biggest city in the world, with an estimated population of over 20 million in the 2020s. An asteroid of this size in the middle of the city would be disastrous.

The experts suggested that if a nuclear deflection options would still be possible, it should certainly be deployed to try and disintegrate the asteroid before it hit Earth. Furthermore the largest part of the city of Dhaka would need to be evacuated for the expected impact date.

The scenario ended at this point, but it left more then sufficient considerations and food for thought to be considered. Day 5 had a number of different information updates over the day, you can find these at:

http://neo.jpl.nasa.gov/pdc15/day5-1.html

http://neo.jpl.nasa.gov/pdc15/day5-2.html

and http://neo.jpl.nasa.gov/pdc15/day5-3.html

 

Lessons learned

Overall the scenario was very useful for the scientists and engineers, mostly because it teaches them what kind of social and civil aspects of a possible meteor strike are of importance: The impact of a NEO would certainly not be of scientific/engineering alone, it would be far more important politically and socially. Through the practice of these scenarios the experts also learn to think from the positions of political leaders, the media, and the public.

A final discussion on the impact scenario at the planetary defense conference 2015.

A final discussion on the impact scenario at the planetary defense conference 2015.

Interesting to note was specifically the discussion that arose over whether or not a nuclear deflection option should be developed and deployed. The development of such a device would certainly bring large political consequences with it.

Furthermore there is a large ethical aspect to consider as well: In the scenario the impact would first take place in the South-China-sea. Such an impact in the sea would trigger a large tsunami that would hit the coasts. It is however very difficult to predict how big such a tsunami would be, and how it much damage it would do. To stop the asteroid from hitting the Earth a number of nations developed kinetic impactors that were designed to deflect the asteroid. However they were unfortunately only partially successful, and this meant that a large city was now put at risk instead. Due to the kinetic impactors the people at the South-China-sea were now save, but the people at Dhaka will lose their homes! Are the states who build and launched the kinetic impactors now responsible for this? This is a major ethical question that needs to be looked at and practice scenarios such as this help to develop a proper policy of how to respond in these kinds of situations.

PDC2015: NEOShield at the conference

A view of the flags of the ESA members states at ESA ESRIN. A model of the Vega rocket can be seen on the left.

A view of the flags of the ESA members states at ESA ESRIN. A model of the Vega rocket can be seen on the left.

The Planetary Defense Conference in Frascati, Italy is in full swing now, with numerous presentations on the NEO subject in the past few days. The NEOShield project is also well represented and the different project participants have also made use of these days to again meet each other in person, something which is not often possible due to the international nature of the project.

 

Meeting of the NEOShield team at the Osservatorio Astronomico in Frascati.

Meeting of the NEOShield team at the Osservatorio Astronomico in Frascati.

On the evening of Tuesday the 15th the team came together for a social event in the “Osservatorio Astronomico” in Frascati. In this old observatory on a hill near the town of Frascati the team members enjoyed a diner together and got to know each other better on a social level, before the real work started again the following morning.

On Wednesday there were a number of presentations from NEOShield organisations. These included presentations on the kinetic impactor and gravity tractor mission designs, but also on complicated software tools that have been developed in the project, and a study investigating how orbits of NEOs look like after they have been deflected by NEOShield. Atop of all the presentations the team also met up during lunch to discuss the technical results of the work they had done since the last meeting.

The NEOShield presentation on the gravity tractor demo mission at the PDC2015.

The NEOShield presentation on the gravity tractor demo mission at the PDC2015.

An interesting NEOShield presentation at the PDC2015: What happens to a NEO after it has been deflected?

An interesting NEOShield presentation at the PDC2015: What happens to a NEO after it has been deflected?

Tuesday and Wedneday were filled from early in the morning till the end of the afternoon with presentations on the physical properties of NEOs, deflection and disruption techniques to push NEOs away from Earth, and mission designs that are considered. The conference will still continue for two more days, with tomorrow (Thursday) presentations on the consequences of a possible impact, disaster planning, and public education.

The next days will also see the development of the PDC 2015 hypothetical impact scenario: A simulated scenario where an asteroid threatens to hit the Earth in the near future. The scenario is progressing each day when more information becomes available. Next Friday we will give you an elaborate account of the scenario on this website, how it developed over the week, and what conclusion was eventually reached. For now you can find more information on it on the PDC website: http://www.pdc2015.org/

PDC2015, day 1: Conference kick-off

Today the Planetary Defense Conference in Frascati, Italy, started. It was the first day of the 5-day conference that brings together the scientists and engineers that are working each day to investigate the threat of NEOs and how to deflect an inbound asteroid.

The conference opened at the ESA ESRIN facilities on Monday morning at 9:00 with a welcome to all visitors from the organisation commission. After that, the first session of presentations quickly started with a number of speakers informing the audience on the recent advances in the international NEO projects that are going on. The progress of NEOShield was presented by Alan Harris, from the DLR.

Alan Harris presenting on NEOShield at the Planetary Defense Conference 2015.

Alan Harris presenting on NEOShield at the Planetary Defense Conference 2015.

After this first session the hypothetical impact scenario was introduced. This is a scenario that is thought up by the organizing committee of the conference to investigate how the world’s experts would react if an asteroid on collision course would be detected. The purely hypothetical scenario now concerns an asteroid designated “2015 PDC” that might hit Earth somewhere in South Asia or the Pacific in 2022. More information on how this scenario progresses during the conference will follow in the next posts on this website.

After the lunch there was another round of presentations focusing on the discovery, tracking and characterization of NEOs. Finally, at the end of the day, all participants came together for some drinks to discuss the findings, the projects, and their (future) cooperation. These kinds of informal talks, between the experts from all around the globe, are maybe the most important things on such a conference, as in this way creative, new ideas are born and new partnerships between international partners are started.

Asteroid 2004 BL86 visible in your telescope

 

Sky map showing the track of asteroid 2004 BL86 across the evening sky. Image credit: universetoday.com, made with Chris Marriott’s SkyMap program.

In our previous article we already introduced you to a big asteroid that is coming into our neighborhood soon: Asteroid 2004 BL86 will pass by at approximately 3.1 lunar distances (or 1.2 million kilometers). Thanks to its size (somewhere around 680m in diameter) the asteroid will even be visible through small telescopes and maybe even through large binoculars.

The asteroid will pass closest to Earth on the evening of Monday the 26th of January. When it does it will be the largest asteroid to approach the direct neighborhood of Earth for quite a long time. The next one is projected to be asteroid 1999 AN10, that will visit in 2027.

Trajectory of 2004 BL86 when it passes by the Earth. Image credit: NASA/JPL-Caltech.

Due to the large size of the asteroid it is expected to reach a magnitude of +9.0 and will be best visible for observers in the Americas, Europe and Africa. It will move across the evening sky at a noticable rate, so if you follow it with a telescope you should be able to see it move through your field of view. It will move at approximately 2 degrees per hour(four Moon diameters).

To track the asteroid you will need a sky map such as this image to find it in the sky. Note that the position of the asteroid might vary slightly depending on where you are on the Earth. You can also use software such as Starry Night, Guide, MegaStar and others to generate such a map and find the current position of asteroid. For this you can find the latest orbital data of the object here.

Next to all the amateur astronomers that will surely be trying to find the asteroid in their telescopes, NASA is also going to have a look using the big radar observatories at Arecibo in Puerto Rico and Goldstone, California. They will try to bounce microwaves of the surface of the asteroid to get a clearer picture of how it actually looks.